Physiology and Pathology of Autoimmune Diseases: Role of CD4+ T cells in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune disease characterised by synovial inflammation leading to bone erosion and to systemic manifestations in patients with long RA duration. Although the aetiology is unknown, several observations make currently clear that CD4 T cells play a key role in the pathogenesis: (1) RA associates with certain polymorphisms of HLA class II molecules, and (2) the repertoire and aging of CD4 T cells as well as the intracellular signalling mediating CD4 T cell activation are altered in RA patients. We describe herein the alterations found in CD4 T cells and the role of these cells in the development and progression of RA.